Add new fedora_nightlies role on openQA prod server
    
    This is to get it off my personal domain (finally). Having it on
    the openQA server is still a bit of a hack, but at least it's
    under fedoraproject.org now and off my hands. This is a consumer
    that runs a static site generator which produces a page full of
    links to the most recent nightly compose images, basically.
    
    Signed-off-by: Adam Williamson <awilliam@redhat.com>